I am dealing with an estate of a deceased lady and would appreciate confirmation of my understanding, who died after April 2017 and:

Survived her husband who himself died in the Estate Duty (September 1973) regime and left c£1,500 unused after the estate passed solely to his wife allowing 10% of today’s NRB to be used on his wife’s estate.

Had a Will with a NRB DT, drafted recently even though there is no new spouse or reason for the DT. (there is also only one beneficiary named in the DT)

Gave away a half share of her house to her only child (and beneficiary of her Will) but still lived there

Am I right in thinking that s102(3) of the Finance Act 1986 means that she had a beneficial interest in all of the property so RNRB would be available to her, provided that a deed of appointment is executed effectively removing the NRB DT from her Will? and
RNRB is available to be transferred from the husband’s estate at 100% as it didn’t exist at the time of his death.